Enterohemorrhagic Escherichia coli (EHEC) is an emerging food- and water-borne pathogen that colonizes the distal ileum and colon and produces potent cytotoxins (Donnenberg, “Infections due to Escherichia coli and other enteric gram-negative bacilli,” in ACP Medicine, WebMD Professional Publishing, Danbury Conn., Chapter 7, pp. 8-1 to 8-18, 2005). After ingestion of contaminated food, humans can develop symptoms ranging from mild diarrhea to the severe, and at times life-threatening, hemolytic uremic syndrome (HUS). Currently, EHEC is the most common cause of pediatric renal failure in the United States (Mead et al., Emerg Infect Dis, 5:607-625, 1999). Several EHEC serotypes cause disease, but the O157 serotype is by far the most common cause of EHEC-related disease in North America, Europe and Japan (Feng, “Escherichia coli,” in Garcia (ed.) Guide to Foodborne Pathogens, John Wiley and Sons, Inc., pp. 143-162, 2001).
EHEC O157:H7 colonization of healthy cattle remains a serious public health threat due to the low numbers of EHEC O157:H7 (e.g., 10-100) necessary to infect a human and to the bulk processing of slaughtered cattle. Methods for detecting and subsequently killing EHEC O157:H7 at slaughter, altering the diet of cattle to reduce the number of intestinal EHEC O157:H7 and immunizing animals to prevent EHEC O157:H7 colonization are being employed to address this problem. Recently, the recombinant production and use of EHEC O157:H7 proteins including recombinant EspA (International Publication No. WO 97/40063), recombinant TIR (International Publication No. WO 99/24576), recombinant EspB and recombinant Initimin (Li et al., Infec Immun, 68:5090-5095, 2000) have been described. However, production and purification of recombinant proteins in amounts sufficient for use as antigens is difficult and expensive.
Thus there is a need in the art for compositions and method for blocking EHEC O157:H7 colonization of cattle and other mammals and, thereby, for reducing shedding of EHEC into the environment. These tools are contemplated to be useful for reduce the incidence of health problems associated with EHEC-contaminated meat and water.